Raith 150, Руководство по эксплуатации системы

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5.2 Filament lifetime
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User
Individual setting of heating and cooling time.
When double-clicking the left mouse button on
Bake out Heat
a value between 1 and 200 hours
may be entered. The same procedure is applicable
for
Bake out Cool
. Cooling periods from 1 to 5
hours will be possible.
STEP 12 ► At the end of the bake out re-insert the plug into the gun head, a pin
has been fitted to the plug, which will allow the cable to only fit in the
correct position. After insertion of the plug the electric supply will be
locked again by means of the black protection cap with bayonet joint,
or the four screws.
Again, in order to avoid any misalignment of the gun head you should
try not to exert any side forces.
STEP 13 ► Now gun and EHT can be switched on again.
5.2 Filament lifetime
Only the main user should turn the gun off. We recommend leaving
the gun on at all times to keep the beam current stable. If the system
will not be used for over 2 days, or if power to the system must be
turned off, shut the gun off. The lifetime of the filament is not effected
by leaving the EHT on.
When turning the gun on, it typically takes 24 hours for the extractor
current to stabilize. After turning the EHT on, it will take between 1
and 3 hours for the beam current to stabilize.
An unstable beam current does not necessarily mean the filament
needs replacement. There are several factors that may contribute to an
unstable beam current, including sample grounding problems and
aperture or column contamination. So please get in contact with Raith
personal to discuss possible origins.
5.2.1 Performing a filament stability test
It is recommended to perform a filament stability test every month.
This helps to identify filament problems and can ensure a long
lifetime, if the filament runs under ideal conditions.
To record the data perform the following steps:
STEP 1 ► Set the EHT to 10 kV and use the 30 µm aperture.